I have one additional information that MIGHT impact you if revert back to 7.1.0 and use VLANs. I think this might have just been a fluke and I don’t have the time or inclination to confirm the root cause.
When I downgraded my firmware to 7.1.0 using InControl I lost my VLANs. The ports were still labeled and appeared to be tagged correctly but things just weren’t working right and the VLANs weren’t showing up in the “Network > LAN > Network Settings” page of the admin interface. It took me a while to figure out what had happened and I ended up just loading a backup config which cleared it up.